Time-resolved investigation of the crystalline and amorphous state in a Phase Change Material for memory applications

Thanks to their ability to switch reversibly between an amorphous and a crystalline state, Phase Change Ma-terials (PCM; typically, Ge-Sb-Te alloys) are attracting enormous attention for application in various types of memories (embedded, neuromorphic…). Many studies, aimed at investigating in situ the phase transition, are reported in the literature but almost none at time scales comparable to those used in real devices (ns). In previous experiments, we were able to induce different crystallized states with nanocrystalline clusters of Ge or GST embedded in an amorphous matrix by laser irradiation; we were also able to amorphize the nanocrystalline clusters of GST and to cycle the crystallization and amorphization of the GST. In the present experiment, we plan to investigate the dynamics of these very early stages of amorphization and crystalliza-tion at ultimate time scales using a laser pump – X-ray probe experimental scheme.